Part5 - Yocto terminology
Terminology -> metadata, recipe, configuration, class, layer
Table of Content
Recipe#
A recipe is a set of instructions that is read and processed by the bitbake (file with .bb extension)
A recipe describes:
- Where to fetch source code
- Which patch to apply
- Configuration options
- Compile options
- Install
- License
Configuration#
Tell the build system what to build and put into the image (file with .conf extension)
Types#
- Machine configuration option
- Distribution option
- Compiler tuning options
- General Common configuration options
- User options (local.conf)
Example machine config#
User local.conf we set the machine for example MACHINE ??= "qemux86-64"
This setting tell the system to load machine configuration option meta/conf/machine/qemux86-64.conf
Class#
Class files are used to share common functionality across recipes (file with .bbclsss extension)
Note
classes useally locate in classes directory inside the meta* directory
usage from recipe#
inherit classname
Layers#
A collection of related recipes.
layer isolate meta data according to functionality
recipes are folders under layer folder
Note
name convention for layer meta-layername
| name | description |
|---|---|
| meta-poky | Distro metadata |
| meta-yocto-bsp | BSP metadata |
BBLAYERS variable present in build/conf/bblayers.conf
bitbake-layers show-layers
Find a layer#
Image#
An image is the top level recipe
image define how the root filesystem is built , with what packages.
ls meta*/recipes*/images/*.bb
Packages#
A package is a binary file with name .deb, .rpm
Packages are produces by recipe
A signal recipe produces many packages. all recipe packages describe is PACKAGES variable